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I am confused regarding significant figures. Consider "Calculate the volume of 2.8 kg of liquid with density of 1.11 g/cm^3"

Then, Volume = 2.8 kg * (cm^3 / 1.11 g) = 2522.522 (where 522 is recurring).

Since the original figure (2.8 kg) has only two significant figures, I thought the answer should be 2.5 kg.

The textbook says the answer is 2.523 kg, which is four significant figures.

Which is correct?

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Unless greater precision is indicated by adding terminal zeroes to the mass measurement (2.800 kg) you should assume only two significant digits. Note also that even if the mass is reported to high accuracy the density is given with only three significant digits. The book is wrong to ask for four significant digits in the answer.

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  • $\begingroup$ I thought it was obvious - but am just starting to learn significant figures so was not sure. Thanks. $\endgroup$ – Starlight Jun 13 '16 at 11:11
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    $\begingroup$ And then also, the answer should be given as $2.5 \cdot 10^{3}$. $\endgroup$ – Jan Jun 13 '16 at 13:34
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Your answer of $2500$ and the book's answer of $2523$ both have four significant figures.

If you want to keep your answer to the same degree of accuracy as the given data with the least number of significant figures, i.e. $2.8$ kg, it is best to express your answer as $2.5\times10^{3}$.

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  • $\begingroup$ Please, add the units in order to make your answer more accurate. $\endgroup$ – user1420303 Jun 14 '16 at 3:14

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